【摘要】：乙炔氣體作為判斷變壓器運行狀態(tài)的一種故障氣體,其濃度的高低反映了變壓器的運行狀況,因此對其濃度的探測在變壓器的維護中具有重要意義。為了準確探測變壓器運行過程中產(chǎn)生的乙炔氣體濃度,為變壓器的維護提供技術(shù)參數(shù),針對基于DFB激光器的共振型光聲光譜技術(shù)痕量乙炔氣體檢測技術(shù)開展研究,對傳統(tǒng)的光聲光譜探測系統(tǒng)進行改進。根據(jù)光聲光譜技術(shù)的理論可知,光聲信號的強度與入射激光的功率成正比,所以在光聲池的出射窗口采用一個平面反射鏡將紅外光再次反射到光聲池中以增加入射光功率,增強光聲信號強度,進一步提高了光聲系統(tǒng)的探測靈敏度。通過一定濃度的乙炔氣體在不同調(diào)制頻率和不同調(diào)制深度下光聲信號強度的變化,確定光聲探測系統(tǒng)的最佳調(diào)制頻率和最佳調(diào)制深度為767 Hz和0.3mV。利用不同濃度乙炔氣體對系統(tǒng)進行標定,然后采用最小二乘法對光聲信號與氣體濃度進行擬合,二者具有很好的線性度。通過Allan方差計算可知,系統(tǒng)在平均時間達到200s時,能夠達到最低探測極限濃度。實驗表明,在一個大氣壓下,積分時間為10ms時,改進后的共振型光聲光譜探測系統(tǒng)對乙炔氣體的最低探測極限濃度達到了0.3μL·L~(-1)。還將小波去噪技術(shù)引入到低濃度下乙炔氣體的光聲信號處理中,有效消除了低濃度氣體光聲信號中的噪聲,提高了信噪比。設(shè)計的共振型光聲光譜探測系統(tǒng)操作簡單,最低探測濃度符合國標中對變壓器維護過程中對乙炔氣體的探測需求,在變壓器維護領(lǐng)域具有廣闊的應用前景。
[Abstract]:Acetylene gas is a kind of fault gas to judge the operating state of transformer. The concentration of acetylene gas reflects the operating condition of transformer, so it is very important to detect the concentration of acetylene gas in the maintenance of transformer. In order to accurately detect the concentration of acetylene gas produced during transformer operation and provide technical parameters for transformer maintenance, the detection technology of trace acetylene gas based on resonance photoacoustic spectroscopy (RASS) based on DFB laser was studied. The traditional photoacoustic spectrum detection system is improved. According to the theory of photoacoustic spectroscopy, the intensity of the photoacoustic signal is proportional to the power of the incident laser, so the infrared light is reflected into the photoacoustic cell again by a plane reflector in the output window of the photoacoustic cell to increase the incident light power. The detection sensitivity of the photoacoustic system is further improved by enhancing the intensity of the photoacoustic signal. The optimum modulation frequency and modulation depth of the photoacoustic detection system were determined to be 767 Hz and 0.3 MV by the variation of the intensity of the photoacoustic signal at different modulation frequencies and different modulation depths of acetylene gas in a certain concentration. The system was calibrated by acetylene gas with different concentrations, and the photoacoustic signal was fitted with the gas concentration by least square method. The calculation of Allan variance shows that the system can reach the minimum detection limit concentration when the average time reaches 200 s. The experimental results show that the minimum detection limit for acetylene gas is 0.3 渭 L L ~ (-1) for the improved resonance photoacoustic spectrum detection system at one atmospheric pressure and integral time of 10ms. The wavelet denoising technique is also introduced into the photoacoustic signal processing of acetylene gas at low concentration, which effectively eliminates the noise in the low concentration gas photoacoustic signal and improves the signal-to-noise ratio (SNR). The resonant photoacoustic spectrum detection system is simple to operate and the lowest detection concentration is in line with the requirement of acetylene gas detection in the transformer maintenance process in the national standard. It has a broad application prospect in the field of transformer maintenance.
【作者單位】： 中國科學院合肥物質(zhì)科學研究院安徽光學精密機械研究所;中國科學技術(shù)大學;
【基金】：國家自然科學基金項目(41575030,21307136)資助
【分類號】：O657.3;TM407

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1 劉斌;蔡解民;;關(guān)于乙炔氣體濃度檢測器安裝位置的研究[J];科技創(chuàng)新與應用;2013年33期

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本文編號：2395584